A TFT-LCD (Thin Film Transistor Liquid Crystal Display) has been widely applied to various display fields due to its advantages of low power consumption, low cost, etc.
Liquid crystal itself does not emit light, so a backlight module for providing display backlight is generally disposed inside the TFT-LCD, and the quality of the backlight module will directly influence the display quality of a liquid crystal display device.
At present, the structure of a common backlight module is as shown in FIG. 1. The backlight module mainly includes a light source 1, a bottom reflector sheet 2 and a light guide plate 3. The light source 1 transmits light from one side of the light guide plate 3. The light is reflected by the bottom reflector sheet 2 and then totally reflected inside the light guide plate 3, so that the light input from one side is effectively turned into a planar light source with good uniformity. In the prior art, to improve the brightness of the light source 1, an LED light bar (Light-Emitting Diode) may be usually used as the light source 1. To reduce the cost of the product, the specific structure of the LED light bar may be as shown in FIG. 2 usually, wherein the LED light bar serving as the light source 1 includes a plurality of LED 11 arranged at intervals. Due to the restriction of the irritation angle of the LED 11 and the distance from the LED 11 to the light guide plate 3, a blind area (area A in the figure) which cannot be directly irradiated by light will be generated between two LED 11. The brightness of this area is relatively dark. However, a luminous area (area B in the figure) on the front side of the LED 11 is relatively bright. Such a structure is likely to cause the backlight source to present appearance of bright/dark-bright/dark area intervals, i.e., causing a hotspot phenomenon. On the other hand, to reduce the loss of light, a lateral reflection film is also adhered to the edge of the light guide plate 3 on two sides of the LED light bar so as to allow light to return back to the light guide plate 3 again, so that light on the edges of the light guide plate is strong, light reflection at the edge area (area C in FIG. 2) is reinforced, and luminescence of the backlight module is not uniform. With the development of narrow frame of the display device, the distance from a light source 1 to the light guide plate is further diminished, so that the hotspot phenomenon or edge light reflection becomes more obvious, the non-uniform luminescence of the bright/dark-bright/dark area intervals is very likely to be observed by naked eyes of a user, and the display effect of the liquid crystal device is thus influenced seriously.